1. Field of the Invention
This invention relates to a panel for use with a supporting grid in a suspended ceiling. The panel is of the type that conceals part or all of the grid, when viewed from below.
2. Background Information
Suspended ceilings are common. They use a grid of metal beams in the form of an inverted T-section, commonly of a 15/16" flange width dimension, to support the panels. The rectangular openings formed by the grid are generally either 24".times.24" or 24".times.48" with correspondingly sized panels. However, irregularly shaped and sized openings and panels are used. Dimensions may be in metric units.
The present invention applies to such suspended ceilings and panels.
The panels are of various ceiling substrates, such as mineral fiber, fiberglass, wood, metal, plastic, or other compositions. They are positioned within the grid opening, and are supported by the grid. The panels are either of the type that expose the grid when the ceilings are viewed from below, or conceal the grid either fully or partially, when viewed from below. This invention involves those panels that conceal the grid when viewed from below.
Panels for a ceiling with exposed grids have a form of upper lip extending over the top of the grid with no lip on the panel below the grid. The panel hangs from the grid, by means of this upper lip. Such a panel is relatively simple to install, position and remove. These panels are not intended to be locked by themselves to the grid.
Panels that conceal the grid from below, on the other hand, pose special problems, since the portion of the edge underlying the grid interferes with any simple installation, positioning, and removal. Panels that conceal the grid, however, are desirable for among other benefits, their appearance, as well as their ability to lock to the grid. The grid can be partially or totally hidden. Additionally, since the panels of this type cover the metal grid, they can have a beneficial effect during a fire, since they serve to insulate the metal from the effects of the heat, particularly where panels are of a fire retardant material, as is generally the case.
Since panels that conceal generally have a lip below the grid as well as one above the grid, there is the potential for locking the panel to the grid. This is especially useful again during a fire, and even more so during a seismic disturbance. Falling panels during a quake present a serious threat to the safety of persons present below the ceiling, and particularly so where gatherings occur such as in auditoriums or public areas.
Panels locked to the grid which give no visual clue to their removal procedure also provide a degree of security against unauthorized access to the space above the ceiling.
Notwithstanding the desirable features of panels that conceal the grid, their use as been limited to a great degree because of problem with installation and removal. In some instances, special shaped grids must be used. In other designs, auxiliary clips or metal attachments to the grid are necessary. Generally, the space above the grid must be used in installing, or removing the panel, requiring such space to be available, thus reducing room height.
In some instances, the installer must position each panel visually from below, with a resulting slowdown in installation. Even without the necessity of visual positioning during installations, in prior art panels that conceal, the installation is a relatively slow procedure.
Often, in prior art, special tools were necessary to install or remove panels that lock or conceal.
Prior art patents relating to panels in suspended ceilings that conceal the grid, and in some instances lock, include U.S. Pat. Nos. 2,218,092, 3,640,012, 3,714,752, 3,900,997, 4,189,895, 4,696,141, 4,760,677, 4,862,663, and U.K. Patent 2,200,151B, and French patents 1,313,963, and 1,227,191. These panels show various edge designs that engage the grid.